Yale’s Most Popular Class Ever: Happiness

The course focuses both on positive psychology — the characteristics that allow humans to flourish, according to Dr. Santos — and behavioral change, or how to live by those lessons in real life. Students must take quizzes, complete a midterm exam, and, as their final assessment, conduct what Dr. Santos calls a “Hack Yo’Self Project,” a personal self-improvement project.

Some students admit that they see the course as an opportunity to take a relaxed lecture with few requirements.

“I wouldn’t have known about the course if not for word of mouth, but it’s low-pressure, and maybe I’ll learn a few tricks to having a less stressful life,” said Riley Richmond, 22, a senior who enrolled in the class with several of his friends.

Charlotte Emerson, 18, a freshman in the course, said she worries some students will take advantage of the lack of accountability that comes with a lecture of this size. For example, Dr. Santos is not monitoring whether students complete weekly “rewirement” assignments, like performing acts of kindness and forming new social connections, Ms. Emerson said.

But while others might see easy credits, Dr. Santos refers to her course as the “hardest class at Yale”: To see real change in their life habits, students have to hold themselves accountable each day, she said.

She hopes that the social pressures associated with taking a lecture with friends will push students to work hard without provoking anxiety about grades. Dr. Santos has encouraged all students to enroll in the course on a pass-fail basis, tying into her argument that the things Yale undergraduates often connect with life satisfaction — a high grade, a prestigious internship, a good-paying job — don’t increase happiness at all.

“Scientists didn’t realize this in the same way 10 or so years ago, that our intuitions about what will make us happy, like winning the lottery and getting a good grade — are totally wrong,” Dr. Santos said.

College courses on positive psychology have a track record of attracting scores of students. At Harvard, about 900 students enrolled in a lecture titled “Positive Psychology” in 2006. What distinguishes Dr. Santos’s course from the one at Harvard in 2006, she said, is that it also focuses on behavioral change.

Still Dr. Santos said she does not plan to offer the course again. Dr. Ahn, of the psychology department, said, “Large courses can be amazing every once in a while, but it wouldn’t be fair to other courses and departments to take all of their students away.”

She added, “It causes conflict, and we can’t afford to offer this every year in terms of teaching fellows and resources.”

Dr. Santos said a multipart seminar-style series on the course material — filmed last year in her home and titled “The Science of Well-Being” — will soon be available for free on Coursera, an online education platform. For now, she is eager to see whether her teachings alter campus life.